#include <stdio.h>
#include <stdlib.h>

#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define INIT_SIZE 10 //初始化表长
#define INCREMENT_SIZE 5 //分配增量


/*
 * 心得: const是固定常量 如果获取的变量是*L 那么需要使用L->length 来获取长度 如果是L那么使用L.length获取长度
 *  *代码取值 那么这个变量就是指针变量 想取地址的话用&e 就是地址了 或者说是指针
 */

typedef int Status;
typedef int Elemtype;

/*
 * 存储结构
 */
typedef struct {
    Elemtype *elem; //存储空间基址
    int length; //当前长度
    int size;  //当前分配的表长大小
} SqList;

/*
 * 初始化一个空的线性表
 */
Status InitList(SqList *L) {
    L->elem = (Elemtype *) malloc(INIT_SIZE * sizeof(Elemtype));
    if (!L->elem) {
        return ERROR;
    }
    L->length = 0;
    L->size = INIT_SIZE;
    return OK;
}

/*
 * 销毁线性表
 */
Status DestroyList(SqList *L) {
    free(L->elem);
    L->length = 0;
    L->size = 0;
    return OK;
}

/*
 * 清空线性表
 */
Status ClearList(SqList *L) {
    L->length = 0;
    return OK;
}

/*
 * 判断线性表是否为空
 */
Status isEmpty(const SqList L) {
    if (0 == L.length) {
        return TRUE;
    } else {
        return FALSE;
    }
}

/*
 * 获取长度
 */
Status getLength(const SqList L) {
    return L.length;
}

/*
 * 根据位置获取元素
 */
Status GetElem(const SqList L, int i, Elemtype *e) {
    if (i < 1 | i > L.length) {
        return ERROR;
    }
    *e = L.elem[i - 1];
    return OK;
}

/*
 * 比较两个元素是否相等
 */
//Status compare(Elemtype *e1, Elemtype *e2) {
Status compare(Elemtype e1, Elemtype e2) {
    if (e1 == e2) {
        return 0;
    } else if (e1 < e2) {
        return -1;
    } else {
        return 1;
    }
}

/*
 * 查找元素
 */
Status FindElem(const SqList L, Elemtype e, Status (*compare)(Elemtype, Elemtype)) {
    int i;
    for (int i = 0; i < L.length; ++i) {
        if (!(*compare)(L.elem[i], e)) {
            return i + 1;
        }
    }
    if (i > L.length) {
        return ERROR;
    }
}

/*
 * 查找前驱元素
 */
Status PreElem(const SqList L, Elemtype cur_e, Elemtype *pre_e) {
    int i;
    for (int i = 0; i < L.length; ++i) {
        if (cur_e == L.elem[i]) {
            if (i != 0) {
                *pre_e = L.elem[i - 1];
                return OK;
            } else {
                return ERROR;
            }
        }
    }
    if (i >= L.length) {
        return ERROR;
    }
}

/*
 * 查找后继元素
 */
Status NextElem(const SqList L, Elemtype cur_e, Elemtype *next_e) {
    int i;
    for (int i = 0; i < L.length; ++i) {
        if (cur_e == L.elem[i]) {
            if (i < L.length - 1) {
                *next_e = L.elem[i + 1];
                return OK;
            } else {
                return ERROR;
            }
        }
    }
    if (i >= L.length) {
        return ERROR;
    }
}

/*
 * 插入元素
 */
Status InsertElem(SqList *L, int i, Elemtype e) {
    Elemtype *new;
    if (i < 1 | i > L->length + 1) {
        return ERROR;
    }
    if (L->length >= L->size) {
        new = (Elemtype *) realloc(L->elem, (L->size + INCREMENT_SIZE * sizeof(Elemtype)));
        if (!new) {
            return ERROR;
        }
        L->elem = new;
        L->size += INCREMENT_SIZE;
    }
    Elemtype *p = &L->elem[i - 1];
    Elemtype *q = &L->elem[L->length - 1];
    for (; q >= p; q--) {
        *(q + 1) = *q;
    }
    *p = e;
    ++L->length;
    return OK;
}

/*
 * 删除元素并返回其值
 *
 */
Status DeleteElem(SqList *L, int i, Elemtype *e) {
    if (i < 1 | i > L->length) {
        return ERROR;
    }
    Elemtype *p = &L->elem[i - 1];
    *e = *p;
    for (; p < L->elem[L->length]; p++) {
        *(p) = *(p + 1);
    }
    --L->length;
    return OK;
}

/*
 * 访问元素
 */
void visit(Elemtype e) {
    printf("%d", e);
}

/*
 * 遍历线性表
 */
Status TraverseList(const SqList L, void (*visit)(Elemtype)) {
    for (int i = 0; i < L.length; ++i) {
        visit(L.elem[i]);
    }
    return OK;
}

int main() {
    SqList L;
    if (InitList(&L)) {
        Elemtype e;
        printf("init_success\n");
        for (int i = 0; i < 10; ++i) {
            InsertElem(&L, i + 1, i);
        }
        printf("length is %d\n", getLength(L));
        if (GetElem(L, 1, &e)) {
            printf("The first element is %d\n", e);
        } else {
            printf("element is not exist\n");
        }
        if (isEmpty(L)) {
            printf("list is empty\n");
        } else {
            printf("list is not empty\n");
        }
        printf("The 5 at %d\n", FindElem(L, 5, compare));
        PreElem(L, 6, &e);
        printf("The 6's previous element is %d\n", e);
        NextElem(L, 6, &e);
        printf("The 6's next element is %d\n", e);
        printf("list:");
        TraverseList(L, visit);
        if (DestroyList(&L)) {
            printf("\ndestroy_success\n");
        }
    }
}
